Metering and mixing device for dental materials



Sept. 6, 1966 F. ROHM ET AL METERING AND MIXING DEVICE FOR DENTAL MATERIALS Filed Nov. 4, 1964 VIE/K470i? Fag. 5

INVENTORS e m mm m m Rh Z Z d/mm F 66 FWH 624% M ATTORNEYS United States Patent 3,271,011 METERING AND MIXING DEVICE FOR DENTAL MATERIALS Fritz Riihm, Stuttgart-Kaltental, Wilhelm Ahrens, Bergen- Enkheim, and Heinz Striihle, Schwahisch Gmund, Germany, assignors to Dr. Walter H. Schmitt G.m.h.I-l., Schwabisch Gmund, Germany Filed Nov. 4, 1964, Ser. No. 408,973 Claims priority, application Germany, Nov. 6, 1963,

W 35,574 1 Claim. (Cl. 25912) This invention relates to a mechanically driven mixing device including a vibrator for mixing dental materials used in the filling of teeth. The material mixing apparat-us is combined with a material metering valve to form a single unit. An apparatus of this general type is disclosed in the published German application DAS 1,101,692.

When the dental materials are being measured out by the metering valve so as to be fed into the mixing portion of the apparatus, it often happens that the pockets in the metering valve shaft are not initially uniformly filled, and after the shaft has been turned, the pockets are not completely emptied. This happens, for example, when the turning knob attached to the metering valve shaft is not turned correctly or when, after the materials have been measured out, the necessarily following mixing of the materials does not take place completely.

This invention is basically composed of a dental materials mixing device attached to a vibrator and connected to a drive motor having a timer switch. It is formed in one unit which includes hoppers for holding the dental materials and a metering valve shaft mounted beneath .the hoppers. In addition, the device is provided with a mechanical locking means adapted to engage the metering valve shaft and controlled by the timer switch.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying drawings in which:

FIGURE 1 is a side elevational view partly in section of this invention;

FIGURE 2 is a cross-sectional view taken on 22 of FIGURE 1; and

FIGURE 3 is a circuit diagram showing the connections between the motor, the timer, and the mechanical locking means.

As shown in FIGURE 1, the device is composed of a housing containing material holding hoppers 12 and 14. Beneath the hoppers is a metering valve shaft 16 containing material receiving pockets 12a and 14a, respectively. This metering valve shaft is extended outside of the housing 10 and terminates in a turning knob 20. In the position shown in FIGURE 1, the pockets receive the dental materials, and by turning knob 20, these pockets discharge the dental materials into a mixing chamber 22. The housing 10 is vibrated by a motor, not shown.

A disc 24 is attached to shaft 16 and has a notch 26 in its periphery. Attached to the housing 10 by a bracket 28 is a solenoid 30 having a plunger 32, The outer end of the plunger has a lug or tongue 36. A spring 38 bears against a flange 39 fastened to plunger 32 to hold lug 36 normally engaged with notch 26 to form a mechanical locking means for valve shaft 16.

As shown in FIGURE 3, the solenoid 30 is connected in parallel with the vibrating and mixing motor 40 and in series with the timer switch 42. In operation, when the device is at rest, the lug 36 is in engagement with the notch 26 so that the knob 20 and metering valve shaft 16 cannot be turned. When the circuit is energized by turning on the timer switch 42, the entire device is vithe line "ice brated by motor 40, and at the same time, the plunger 32 in the solenoid 30 withdraws the lug 36 from the notch 26. This ensures that the vibrating device will first fill the pockets 12a and 14a completely and uniformly before the knob 20 can be turned. Also, after the knob has been turned and the materials dropped into mixing chamber 22, the Vibrations ensure that the pockets 12a and 14a will be complete-1y emptied and that the materials will be completely mixed as long as motor 40 is running. When the mixing time 'has expired, as set by timer switch 42, then the spring 38 returns the lug 36 into engagement with the notch 26.

The motor 40 and the solenoid 30 are constructed to be operated on either a v. or a 220 v. electrical ci-rcuit.

The mechanical lock composed of the solenoid 30 results in less deviation in the mixture of the dental ma terials 'because of making sure that the device is vibrate-d by the switch and motor circuit during the metering and mixing of the dental materials. For example, in mixing approximately 600 mg. of amalgam, the actual mixing weights varied from *-0.2 to 0.8%, whereas heretofore variations of :13 to 2.7% occurred. This decrease in the percent of Variations is due to the fact that the measuring pockets are always uniformly and fully filled and thereafter these pockets are completely emptied without leaving any residue in the pockets.

This invention is especially suitable when used with a mixing device having a substantially horizontally positioned tube comprising part of the mixing chamber and which is used to simultaneously mix and feed the mixed material into a cup fastened to the end of the tube.

Thus, according to this invention, it is no longer possible to move the dental materials from the hoppers into the mixing chamber without first putting the vibrating mechanism into operation. Otherwise the materials might clog, which would lead to erroneous mixes. Because the mixing tube is vibrating, all of the mixed material will be fed into the receiving cup without leaving any deposits of amalgam in the mixing chamber.

Having now described the means by which the objects of the invention are obtained, we claim:

In a power driven mixing device for metering and mixing dental materials and having a plurality of hoppers for holding dental materials, a pocketed metering valve shaft rotatably mounted beneath said hoppers, electric motor means for shaking said device, and timer switch means joined to said motor, the improvement comprising a disc secured to said shaft, a notch in the periphery of said disc, solenoid locking means act-ua-table by said timer switch means engageable with said notch to prevent the rotation of said shaft until said motor means has started, and spring means for holding said solenoid means normally engaged with said notch.

References Cited by the Examiner UNITED STATES PATENTS 420,3 85 1/ 1890 Horan 222-497 1,866,294 7/1932 Chott 222l97 2,779,502 1/ 7 Ackerman 22248 2,800,256 7/ 1957 Di NuZZo 2221 36 X 2,844,284 7/1958 Ackerman 222136 X FOREIGN PATENTS 89, 83 8 11/ 1921 Switzerland.

IRVING BUNEVICH, Primary Examiner.

WALTER A. SCHEEL, Examiner.

J. M. BELL, Assistant Examiner. 

